JPH04224454A - Driving sliding controller (asr device) and brake anti-lock device (abs device) in surface travelling car - Google Patents

Abstract

PURPOSE: To ensure an operation of an ABS device and to reduce costs by emptying a pressure accumulator connected to a return line in a brake circuit after drive slip control process is finished in an ASR device and the ABS device in a traveling vehicle provided with multiple hydraulic circuit type brake equipment in which a return-flow pump for a brake circuit of a driven wheel is used as an auxiliary pressure source for the ASR device. CONSTITUTION: A return-flow pump 27 continuously carries out a conveying operation over a delay time range commencing with the disappearance of a situation requiring control, and an ASR device control valve 71 arranged for shutting off a brake device 18 from a main brake line 24 of a brake circuit for a driven wheel is held in a shut-off position assigned to the ASR device operation. As a buffer accumulator 53 is emptied, effect of an ABS device can be ensured, and no relief valve is required.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a drive slip control device (
ASR device) and brake anti-lock device (ABS
equipment).

0002

[Prior Art] Combining an ASR device and an ABS device in this way has already been disclosed in Patent No. 380 of the Federal Republic of Germany.
2133A1, in which the ASR device operates on the principle of further decelerating a driving traveling wheel that has a tendency to spin by activating its wheel brake, and the ABS device operates on the principle that at least the brake circuit attached to the driving traveling wheel It works on the reflux principle.

[0003] In this case, the return pump of the ABS device attached to the brake circuit of the driven running wheels is used as an auxiliary pressure source for the ASR device. The outlet pressure of this auxiliary pressure source is supplied to the controlled wheel in the brake pressure buildup process of the drive slip control, and the brake pressure control valve of the ABS system is used for a similar purpose within the framework of the ASR system. . During operation of the ASR device, the outlet pressure chamber of the brake device, which is attached to the brake circuit of the driven traveling wheel and is generally designed as a tandem master cylinder, is
The main brake piping of the brake circuit of the driven traveling wheels is shut off by the ASR device control valve. This ASR
The basic position of the device control valve is the through-flow position associated with normal braking operation and braking operation corresponding to anti-lock control. A pressure limiting valve is connected in parallel to this ASR device control valve, and the "overpressure" generated in the main brake piping of the brake circuit of the drive traveling wheel during drive slip control operation is absorbed by the pressure limiting valve. to the brake equipment and via this to the “pressure-free” storage tank of the brake equipment.

A damping accumulator, which is designed as a low-pressure accumulator, is connected to the return line of the brake circuit of the drive wheel. This buffer accumulator continuously recirculates the brake fluid discharged from one or both wheel brakes of the brake circuit of the driving traveling wheels during the brake pressure extinction process of anti-lock control and drive slip control. It is absorbed "quickly" by the pump into the outlet pressure chamber of the brake system attached thereto or into the brake fluid storage tank of the brake system before being returned in several transport strokes of the reflux pump.

[0005] This buffer accumulator is filled to a pressure of approximately 15 bar at the end of the pressure reduction phase of the drive slip control. Anti-lock control is required when braking due to interruption of drive slip control operation at the moment when the buffer accumulator is filled, and at low brake pressures, for example when the vehicle is driving on an icy or snowy road surface. When this braking is performed in the driving state assumed, the buffer accumulator is "full", so regarding the brake pressure disappearance process of anti-lock control,
The brake pressure is not dissipated, or at most can dissipate only very slowly. In order to prevent the risk of the rear wheels of the vehicle locking up as a result, in the known control device a 2-port 2-position solenoid valve is connected between the buffer accumulator and the brake fluid storage tank of the brake system. ing. This switching solenoid valve is placed in a flow-through position during the brake pressure dissipation phase of the drive slip control, so that brake fluid is discharged from the buffer accumulator directly into the brake fluid storage tank. This accumulator release valve is malfunctioning (
In the event of leakage or getting caught in the flow-through position,
The brake circuits of the driven wheels are emptied and therefore deactivated when the anti-lock control responds to this.
This poses a major safety risk.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ASR device combined with an ABS device of the type mentioned at the outset, at an overall low cost, which eliminates the risk of deactivation of the brake circuits of the driving wheels. The objective is to improve the process so that it is sufficiently reduced.

[0007] This object is achieved according to the invention by the measures specified in the features of patent claim 1.

Based on the present invention, the brake circuit of the drive running wheels is activated by shutting off the recirculation pump and returning the ASR device control valve to the basic position corresponding to braking operation with a delay after the end of the drive slip control request state. Even when permanently sealed, the buffer accumulator is emptied rapidly by the reflux pump being driven over a delay period. The danger of the brake circuit being shut down due to activation of the anti-lock control in the brake circuit of the driven running wheels is avoided, and furthermore, since no accumulator release valve is required, the construction as a whole can be simple and inexpensive. When the drive slip control stroke is interrupted by activation of the brake equipment, while the ASR equipment control valve is still shut off, the reflux pump conveys from the buffer accumulator to the wheel brakes, which then actuate against the master brake cylinder. Despite the blockage, brake pressure can build up.

As proposed in claim 2, the delay time width is determined by a timing element of the electronic control unit in such a way that this time width has a constant value, of which 400 ms is suitable in a simple case. .

[0010] Claims 3 and 4 propose an advantageous and simple embodiment for making it possible to change the delay time width as required.

[0011] The electromagnetic valve which can be implemented in a simple manner according to claims 5 and 6 allows a precisely metered supply of brake fluid to the reflux pump with respect to drive slip control. This prevents the brake fluid from having to be discharged too frequently via the pressure limiting valve into the brake system, thereby preserving both the pressure limiting valve and the brake system. Furthermore, in the event of a failure in which the prefill pump does not shut off, it is avoided that additional brake fluid is delivered to the brake circuit during antilock control. Its transportation may cause damage to the brake equipment.

As proposed in claim 7, a low-pressure accumulator is provided which can be filled by a prefilling pump and is designed according to claim 8. A small prefilling pump can therefore advantageously be used, which is likewise integrated into the hydraulic circuit of the ASR and ABS device together with a small accumulator, in which case the filling operation of the prefilling pump is defined in claim 9. can be easily controlled based on

If, as proposed in claim 10, the return pump of the brake circuit of the driven traveling wheels is designed as a self-priming pump, no prefilling pump is required and the entire control device is structurally free. can be considerably simplified.

The inlet control valve proposed in claim 11 allows fine adjustment of the outlet pressure of the reflux pump.

If the inlet control valve is designed according to the features of claim 12, it can be connected together with the ASR device control valve.

The buffer chamber inserted around the reflux pump according to claim 13 provides additional safety in that a sufficient amount of well-degassed brake fluid is available in drive slip control operation. .

In this connection, the insertion of a pressure limiting valve into the hydraulic circuit of the ASR device, as proposed in claim 14, is likewise particularly advantageous in order to sufficiently avoid the incorporation of air into the brake fluid. It's advantageous.

The solenoid valve inserted between the outlet of the reflux pump and its supply pipe according to claim 15 and controlled according to claim 16 enables the self-priming reflux pump to be braked during the anti-lock control process. To easily prevent liquid from being sucked in from a storage tank.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments shown in the drawings. In Figure 1, a road vehicle is shown, the whole number being 10.
This is indicated by a hydraulic dual-circuit brake system. This road vehicle has a brake anti-lock device (A
BS device) 11 and a drive slip adjustment device (ASR device) 12 that utilizes the working parts of this ABS device 11.

For this vehicle, it is important to note that it has a rear axle drive and wheel brakes 1 of the non-driven front wheels.
It is assumed that the wheel brakes 3 and 14 of the driving rear wheels are combined in the form of a front axle brake circuit I, and the wheel brakes 16 and 17 of the driven rear wheels are combined in the form of a rear axle brake circuit II.

In order to supply brake pressure to both brake circuits I, II, which are designed as hydrostatic brake circuits, a brake system is provided which is designed as a tandem master cylinder and is designated as a whole by 18. This brake system has outlet pressure chambers 19, 21 associated with the two brake circuits I, II, respectively. In these outlet pressure chambers 19, 21, (static) brake pressures PVA, PHA are formed, which are controlled by the force Kp with which the driver operates the brake pedal 22. These brake pressures PVA, PHA are applied to the wheel brakes 13, 14 to 16, 1 via the main brake pipes 23 to 24 of the front axle brake circuit I to the rear axle brake circuit II.
7.

The front axle brake circuit I is then connected to the primary outlet pressure chamber 19 of the tandem master cylinder 18, and the rear axle brake circuit II is connected to the secondary outlet pressure chamber 21.

Regarding the ABS device 11, it acts on the front axle brake circuit I and the rear axle brake circuit II based on the recirculation principle, that is, in the brake pressure reduction process of anti-lock control, the wheel being controlled The brake fluid discharged from the brakes 13 and/or 14 and/or 16 and/or 17 is transferred to the respective brake circuit I or II.
Outlet pressure chamber 1 of master cylinder 18 attached to
It is assumed that the number will be returned to 9 to 21. For this purpose, a separate return pump 26 or 27, which is generally designed as a free piston pump, is provided for each of the two brake circuits I, II. These reflux pumps 26, 27 have an electrically controlled drive, which is not shown, but generally both reflux pumps 26
, 27 are formed as an eccentric wheel type drive device that drives them in common.

Main brake piping 2 of front axle brake circuit I
The two brake branch pipes 29, 31 coming out from the branch point 28 of No. 3 and the brake branch pipes 33, 34 coming out from the branch point 32 of the main brake pipe 24 of the rear axle brake circuit II are connected to the front axle brake circuit I. wheel brake 1
3, 14 to the wheel brakes 16, 17 of the rear axle brake circuit II, respectively, inlet valves 36, 37 to 38,
It serves to supply brake pressure via 39. These inlet valves 36, 37 to 38, 39 are connected to the ABS device 1.
1 or the ASR device 12 is not responding, it assumes the illustrated basic position 0 (through-flow position), and the wheel brake cylinders of the front wheel brakes 13, 14 or the rear wheel brakes 16, 17 are closed to these inlet valves 36-39. Through-flow passage 4
1 and is connected to main brake piping 23 or 24 of each brake circuit I or II. These inlet valves 3
In the basic position 0 of 6 to 39, when braking is performed "normally", that is, without anti-lock control, the brake device 18
Brake pressure is built up and dissipated by the actuation of the brake.

In the illustrated embodiment, the inlet valves 36 to 39 are designed as two-port, two-position switching solenoid valves.
When these switching electromagnets 42 are controlled by output signals of an electronic control unit 43 provided for controlling the functions of the ABS device 11 and the ASR device 12, it is difficult to determine which running wheels the control action should be applied to. Accordingly, one or several of them are controlled to their excitation position I (blocking position). In this excitation position I, the wheel brakes 13 and/or 14 and/or 16 and/or 17, which are controlled by the front axle brake circuit I and the rear axle brake circuit II, are respectively disconnected from the main brake lines 23 and 24.

Further, the wheel brake cylinders of the front wheel brakes 13, 14 and the rear wheel brakes 16, 17 are connected to the outlet valve 4.
4,46 to 47,48 are connected to a return line 49 of the front axle brake circuit I and a return line 51 of the rear axle brake circuit II. These return piping 49,5
Also connected to 1 are damping accumulators 52 and 53, each of which is designed as a low-pressure accumulator. Their storage capacity corresponds to approximately half the brake fluid volume that must be supplied to the front axle brake circuit I or the rear axle brake circuit II in order to obtain the maximum brake pressure PVA, PHA.

The outlet valves 44, 46 to 47, 48 are similarly formed as two-port, two-position switching solenoid valves, and by energizing their control magnets 54 with the control output signal of the electronic control unit 43, Depending on whether the ABS device 11 reacts to the wheels, one or more of them can be moved from their basic position 0 (blocking position) to their energizing position I (through-flow position).
controlled by. In this energized position, the wheel brakes 13 and/or 14 to 16 and/or 17, which are controlled in such a way that the brake pressure in the front axle brake circuit II or the rear axle brake circuit II is extinguished, are energized via the through-flow channel 56 of the respective outlet valve. and is connected to the return pipes 49, 51 of the front axle brake circuit I or the rear axle brake circuit II.

Inlets 57, 58 of both reflux pumps 26, 27
are connected to the return line 49 of the front axle brake circuit I and the return line 51 of the rear axle brake circuit II via inlet check valves 59 and 61, respectively. These inlet check valves 59, 61 are connected to respective return pipes 49, 51 and buffer accumulators 52, 53 connected thereto.
It is biased in the opening direction by a very high pressure in the return line 49, 51 and held in its closed position by a very high pump inlet pressure than in the return line 49,51.

The closing force of the valve spring of this inlet check valve 59, 61 is comparable to a pressure of 2 to 3 bar in its typical design.

It is assumed that the damping accumulators 52, 53 are identically designed as piston-spring accumulators. Typically, the bias pressure of the accumulator springs of the buffer accumulators 52, 53 is comparable to a somewhat higher pressure, e.g. 4 to 6 bar, so that the absorption capacity of the buffer accumulators 52-53 is not fully utilized. It is designed to correspond to a pressure of approximately 10 to 15 bar when applied.

Pump outlets 62 and 63 of both return pumps 26 and 27 are connected to main brake pipe 23 of front axle brake circuit I and main brake pipe 24 of rear axle brake circuit II through outlet check valves 64 and 66, respectively. These outlet check valves 64, 66 are then biased in the opening direction by a very high pressure at the respective pump outlet 62 or 63, and by a very high pressure at the respective main brake line 23 or 24. is biased in the shielding direction. A buffer chamber 67 and a throttle 68 are connected in series between these outlet check valves 64, 66 and the respective main brake pipes 23 to 24 for the purpose of damping noise. The design of the outlet check valves 64, 66 is similar to that of both reflux pumps 26.
, 27 corresponds to the design of the inlet check valves 59, 61.

The ABS device 11 described above is mass-produced, and its structure and operation are well known, so
The explanation thereof will be omitted here.

The functional components of the ABS device 11 described with respect to the rear axle brake circuit II, ie with respect to the drive wheel brake circuit, namely the brake pressure regulating valves 38, 39, 4
7, 48, the buffer accumulator 53 and the reflux pump 27 serve the same purpose within the framework of the ASR device 12. This ASR device 12 operates on a principle known per se, in which a running wheel with a tendency to spin is slowed down again by the automatic action of its wheel brakes 16 and 17.

As an auxiliary pressure source necessary for this purpose, AS
In the R device 12, the reflux pump 27 of the rear axle brake circuit II is used. The connection point 69 of the axle brake circuit II to the main brake line 24 can then be isolated from the outlet pressure chamber 21 of the tandem master cylinder 18 associated with the rear axle brake circuit II by means of the ASR device control valve 71.

This ASR device control valve 71 is formed as a 2-port 2-position switching solenoid valve, and its basic position 0 is a through-flow position, which corresponds to normal braking operation and braking operation under anti-lock control. The energized position I is the cutoff position and corresponds to drive slip control operation.

Furthermore, an electric prefill pump 73 is provided within the framework of the ASR device 12. This pump 73 conveys brake fluid from the storage tank 74 of the brake system 10 to the inlet 58 of the return pump 27 of the rear axle brake circuit II during drive-slip controlled operation. In that case, between the outlet 76 of the prefill pump 73 and the inlet 58 of the reflux pump 27 there is a further check valve 77 which acts as an inlet check valve of the reflux pump 27.
is provided. This check valve 77 is biased in the opening direction by the outlet pressure of the prefill pump, which is much higher than the inlet 58 of the reflux pump, and is otherwise blocked.

Pressure limiting valve 78 for prefill pump 73
are connected in parallel, and by means of this pressure limiting valve 78 the outlet pressure of the prefill pump 73 is limited to a value of 20 bar.

Furthermore, the outlet 76 of the prefill pump 73 is connected directly to the main brake line 24 of the rear axle brake circuit II via a further check valve 79, which check valve 79 also controls the pressure in the main brake line 24. is biased in the opening direction by the outlet pressure of the prefill pump 73 which is much higher than the
Otherwise it will be blocked. The closing force of the valve springs of the two check valves 77, 79 corresponds to a pressure of approximately 2 to 3 bar.

Further, a pressure limiting valve 81 is connected in parallel to the ASR device control valve 71. When the ASR device is operating, the rear axle brake circuit I is
The pressure supplied to the main brake line 24 of I is limited by its pressure limiting valve 81 to a value of approximately 200 bar.

To explain the operation of the ASR device 12 described above with reference to its functional elements, as a typical state,
For example, assume a driving condition in which the drive slip of the right rear wheel increases more sharply than that of the left rear wheel. In such a state, the drive slip λA of the rear wheel that has a tendency to spin is, for example, 3
As soon as the 0% reaction threshold is exceeded, the prefill pump 73 and the reflux pump drive are switched on, which simultaneously controls the ASR device control valve 71 into its shut-off position I and in the same way prevents the spin tendency. The inlet valve 38 of the left rear wheel without the front wheel is controlled. Note that the drive slip λA is expressed by the following equation. λA=(VR-VF)/VR In this equation, VR is the circumferential speed of the running wheel in question, and VF is the running speed, which is assumed to be the average value of the circumferential speed of the non-driven front wheels. The pressure built up in the main brake line 24 of the rear axle brake circuit II by activation of the reflux pump 27 is now supplied to the right-hand rear wheel, which has a tendency to spin, thereby further decelerating the right-hand rear wheel. The wheel brakes 17 are supplied to the wheel brakes 17 for a limited period of time before the spin tendency of the controlled rear wheels has completely disappeared, i.e. before its drive slip has been reduced below the lower threshold. In order to maintain the brake pressure at the value obtained up to that time, the inlet valve 39 is switched into its blocking position I. After the drive slip has fallen below the lower threshold, the forward drive torque is again transmitted to the vehicle in the desired magnitude for the controlled drive wheel, and at the same time good drive stability is ensured. During the brake pressure maintenance process of drive slip control, the reflux pump 27 and its prefill pump 73 continue to operate. If the spin tendency of the right-hand rear wheel increases again during the pressure holding process, the inlet valve 39 of the wheel brake 17 is returned to the through-flow position 0, that is, the brake pressure building position, so that the brake pressure in the wheel brake 17 increases again. It will be done.

The tendency of the running wheels that are subsequently controlled to spin is, if necessary, further eliminated after the implementation of a further braking pressure retention process, which is caused by the electronic control unit 43
In this case, the driving slippage of the running wheel in question is recognized when it falls below the lower threshold value λmin. At this time, the outlet valve 48 is switched to its through-flow position I, and the inlet valve 3
By continuing to hold 9 in its cut-off position, the brake pressure at wheel brake 17 is reduced. In this case, in this pressure reduction process of drive slip control,
The action of the buffer accumulator 53 and the reflux pump 27 is completely similar to the action during antilock control operation. After that, the drive slippage of the running wheels becomes a problem (
When the lower limit value remains below the lower limit value for a minimum period of time (after falling below the above-mentioned lower limit value), the outlet valve 48 is first returned to its basic shutoff position 0. This corresponds to the point at which the control request state is considered to have ended. After this point, the reflux pump 27 continues to operate for a period sufficient to completely empty the still partially filled buffer accumulator 53, ensuring that the buffer accumulator 53 is empty. ASR device control valve 7 until pressure is reached.
1 is held in its blocking position I, and both rear wheel brakes 16,
17 inlet valves 38, 39 are held in their shut-off position I.

The reflux pump 27 is then also shut off, and the inlet valves 38, 39 and the ASR device control valve 71 are returned to their basic position 0 again, so that the brake system 10 and its control device 11, 12 are in a so-called "control neutral" state. The operating state is achieved again together.

[0043] Inlet valves 36 to 39 of the reflux pump drive device;
Outlet valves 44, 46-48, prefill pump 73 and AS
The control signals necessary to properly control the R device control valve 71 in the sense of anti-lock control or drive slip control operation are provided by an electronic control unit 43 that is commonly provided for both control methods. Wheel rotation speed sensors 82 attached to the wheels and drive wheels, respectively
~85 output signals are obtained by processing them based on known prerequisites. Those wheel rotation speed sensors 82
.about.85 generates an output signal representing the circumferential speed of each wheel in the form of level and/or frequency, the temporal variation of which also contains information regarding the acceleration and deceleration state of each running wheel.

[0044] A minimum period in which the reflux pump 27 operates beyond the end of the control request condition and the ASR device control valve 71 and the inlet valves 38, 39 of the brake circuit II of the driven traveling wheels remain held in their shut-off position. The time width Δtr is determined by a timing element provided within the frame of the electronic control unit 43.

The end of the ASR device control request state is recognized by the electronic control unit 43, ie one of the drive wheels
This is recognized by the "final" signal which indicates that there is still a drive slip that has decreased by more than the permissible minimum value λmin. Prior to such a state, a brake pressure extinction process takes place in the last wheel brake of the drive wheel, which is forced to be controlled according to the control philosophy customary for the drive slip control exerted by the brake actuation. This further shows that the inlet valves 38, 39 of both wheel brakes 16, 17 of the driven traveling wheels are in their shut-off position, and that at the end of this state the outlet valve of the driven wheel brake under control is in its shut-off basic position 0. The outlet valve of the wheel brake of the running wheel which is in
It means to take. In the above-mentioned state in which drive slip control is required at this outlet valve, that is, at the right rear wheel of the traveling vehicle, the outlet valve 48 is in its excitation position I (through-flow position) at the end of the control required state, and the right rear wheel is not braked. A drop in the signal indicating that the slip is greater than the above-mentioned minimum value λmin causes it to return to its blocked basic position 0. At this point, the inlet valves 38, 3 attached to both wheel brakes 16, 17 of the brake circuit II of the driving traveling wheels
9 is in its (interrupted) excitation position I, and from this point on, in the simplest case, a delay time interval Δtr, determined by the timing element of the electronic control unit 43, begins, over which time the brake circuit of the driven traveling wheels is activated. Both inlet valves 38, 39 of brake circuit II remain in their shut-off position, the reflux pump 27 of this brake circuit II continues to operate (if the prefill pump 73 is shut off), and the ASR device control valve 71 also remains in operation. It is held at its (excitation) cutoff position I.

Therefore, during this delay time width Δtr, the buffer accumulator 53 of the brake circuit II of the driving running wheel is ``empty'', and the pressure is absorbed by the buffer accumulator 53 in the ``final'' pressure reduction process of the drive slip control. The brake fluid is returned via the pressure limiting valve 81 to the outlet pressure chamber 21 of the brake equipment attached to the brake circuit II of the driven traveling wheels, and via this to the brake fluid storage tank 74 of the brake equipment. It will be done.

This delay time width Δtr is such that, on the assumption that the buffer accumulator 53 is effectively emptied within that time, that is, that the buffer accumulator 53 is formed as a piston-spring accumulator, the piston is It is determined to reach a basic position associated with the minimum volume of the accumulator chamber.

This "discharge operation" following the operation of the ASR device of the buffer accumulator 53 attached to the brake circuit II of the drive running wheels is such that the drive slip control process is also "interrupted" by the operation of the brake system 10. This is also done as described above. Due to this "discharge operation", the buffer accumulator 53 has an absorption capacity,
That is, it is ensured that the brake pressure is dissipated sufficiently quickly when the braking immediately causes a reaction of the ABS device.

If the delay time width Δtr is fixed, it is typically 400 ms, and after the expiration of this delay time Δtr, the inlet valves 38, 39 are switched back to their basic positions and the reflux is stopped. Pump 27 is shut off and A
The SR device control valve 71 is likewise returned to its basic position 0 (through-flow position), so that the brake installation 10 is in any case ready again for a subsequent braking operation or for a drive-slip control operation.

In the embodiment shown, a pressure monitor 86 is provided which monitors the pressure in the buffer accumulator 53. This pressure monitor 86 is connected to the buffer accumulator 5.
3, which output signal is used to initiate the shutoff of the reflux pump 27 and the return of the ASR device control valve 71 and the inlet valves 38, 39 to their home positions. This output signal is then introduced as an input to the electronic control unit 43, which electronic control unit 43
processes this signal so that the delay time width Δtr is shortened according to demand.

Provided that the damping accumulator 53 is configured as a piston-spring accumulator, the pressure switch 8
A limit switch 87 can also be used instead of 6. This limit switch 87 generates a signal that starts the end of the delay time width Δtr when the piston (not shown) of the buffer accumulator 53 reaches a basic position corresponding to the minimum volume of the accumulator chamber.

In the illustrated embodiment, prefill pump 73
An outlet pipe 88 emerges from the branch point 89, which branches off on the one hand via a non-return valve 79 into the main brake pipe 24 of the brake circuit II of the driven traveling wheels, and on the other hand with the reflux pump 27 of this brake circuit II. to its inlet 58 via an inlet check valve 77 . This outlet piping 88 is controlled by an output signal from the electronic control unit 43 by a two-port two-position switching solenoid valve 91 to be shut off or opened. This two-port, two-position solenoid valve 91 is therefore used to meter the pressure medium flow introduced into the reflux pump 27 (by pulse control), thereby also
Brake circuit I of the drive wheel during drive slip control operation
It is used directly for metering the brake pressure supplied to the wheel brakes 16 and/or 17 of I. This 2-port 2-position switching solenoid valve 91 is a "small" type that is connected to the outlet piping 88 of the pre-filling pump 73 between the outlet check valve 93 of the pre-filling pump 73 and the 2-port 2-position switching solenoid valve 91.
It can also be used as a filling control valve for filling the accumulator 92. The storage volume of this accumulator 92 corresponds to the maximum intake volume of brake circuit II of approximately 5 cm@3. The pressure level until the small accumulator 92 is filled then corresponds to the maximum outlet pressure level of the prefill pump 73.

A pressure switch 94 is provided to control the filling of the small accumulator 92. This pressure switch 94 indicates that the accumulator pressure is approximately 70% of the maximum pressure.
, an output signal is generated which causes the prefill pump 73 to operate. It is assumed that the small accumulator 92 is designed as a piston-spring accumulator, in which case a limit switch 96 can also be used instead of the pressure switch 94 for controlling the filling operation. This limit switch 96 generates a fill control signal from a predetermined position on the accumulator piston. In that case, in order to enable the accumulator filling operation of the prefill pump 73 to be performed only by its control, a basic 2-port 2-position switching solenoid valve 91 is used to shut off the outlet piping 88 of the pre-fill pump 73, as shown in the figure. Advantageously, the position is a blocking position.

1 and the above-mentioned variants of the ASR device 12, the reflux pump 27 of the brake circuit II of the drive wheel is a non-self-priming pump, for example in the case of a standard ABS device 11. An implicit prerequisite is that it is configured as a free piston pump, as is generally available.

Unlike this, in the case of the embodiment shown in FIG.
The return pump 27' of the brake circuit II of the driven traveling wheels is designed as a self-priming pump, the inlet 58 of which is connected via an inlet check valve 77 upstream to the brake fluid storage tank of the brake system 18. It is directly connected to a brake fluid supply pipe 97 coming out from 74. In that case, the valve spring of the inlet check valve 77 of this self-priming reflux pump 27' is designed for a small return force, which only corresponds to a pressure of about 0.1 bar. Self-priming pump 27'
A 2-port 2-position switching solenoid valve 98 is connected between the outlet check valve 66 and the supply pipe 97. This two-port, two-position switching solenoid valve 98 is located spatially close to the inlet check valve 77 of the reflux pump 27'. The basic position 0 of this two-port two-position solenoid valve 98 is a through-flow position in which the reflux pump 27' circulates and conveys the brake fluid from its outlet 63 to its inlet 58.

This 2-port 2-position switching solenoid valve 98 is an AS
When the R device 12 is activated, it is expediently switched over the same time period together with the ASR device control valve 71 into its excitation position I (blocking position). If the anti-lock control responds,
The 2-port 2-position solenoid valve 98 is switched to its shutoff position I only during the pressure reduction process of the anti-lock control, i.e. only when the reflux pump 27' has to return brake fluid to the brake system 18. During the remainder of the process, the reflux pump 27' remains in the illustrated flow-through position 0, in which it operates in circulation. In that case, the "long" supply pipe 97
is significantly greater than the flow resistance provided by the inlet check valve 77 of the reflux pump 27'.

Although there are some reference numerals in FIG. 2 which have not been mentioned in the above description, the reference numerals correspond to the functional elements of the brake equipment 10 in FIG. 1, so please refer to the description in FIG.

The same holds true for the description of the embodiment shown in FIG. In FIG. 3, the reflux pump 27' is likewise designed as a self-priming pump, the inlet check valve 77 of which corresponds to the design of the inlet check valve in FIG.

The brake fluid supply pipe 97' communicates with the inlet check valve 77 of the reflux pump 27' via a buffer chamber 99. The volume of the buffer chamber 99 corresponds to the maximum amount of brake fluid that can be forced into the wheel brakes 16, 17 of the brake circuit II of the driving wheels. The brake fluid supply line 97' here emerges directly from the outlet 72 of the outlet pressure chamber of the braking device 18, which is associated with the brake circuit II of the drive wheel. While the brake device 18 is not in operation, its outlet pressure chamber communicates with the brake fluid storage tank 74 of the brake device 18 . A 2-port 2-position switching solenoid valve 100 is further provided as a function control valve for the operation of the reflux pump 27'. In its optional operating position 0, I, the buffer chamber is blocked from or connected to the outlet 72 of the brake device 18. The basic position 0 of this function control valve 100 is
This is the cutoff position maintained during normal operation and during braking operation subject to anti-lock control.

The energized position I (through-flow position) of this function control valve 100 corresponds to the operation of the ASR device, in which case this function control valve 100 operates in the same way for the same time period together with the ASR device control valve 71. is held at excitation position I.

The pressure limiting valve 81 that limits the pressure in the main brake pipe 24 of the brake circuit II of the driving traveling wheels allows the brake fluid to flow from there to the buffer chamber 99 when excessive pressure is applied to the main brake pipe 24. is inserted into the hydraulic circuit.

[Brief explanation of the drawing]

1: Hydraulic circuit diagram of a brake installation of a road vehicle in which an ASR device and an ABS device are combined according to the invention and the return pump of the brake circuit of the drive wheel is used as a pressure source for drive slip control; FIG. .

2 shows a hydraulic circuit diagram of an ASR device functionally corresponding to the control device in FIG. 1 with a self-priming reflux pump; FIG.

3 shows a hydraulic circuit diagram according to FIG. 2 of a further embodiment with a self-priming reflux pump; FIG.

[Explanation of symbols]

10 Brake equipment 12 ASR device 16 Wheel brake 17 Wheel brake 18 Brake device 24 Main brake piping 27 Reflux pump 43 Electronic control unit 53 Buffer accumulator 71 ASR device control valve 86 Pressure monitor 87 Limit switch 88 Supply piping 91 2 port 2 position switching solenoid valve 92 Low pressure accumulator 94 Pressure monitor 96 Limit switch 100 2 port 2 position switching solenoid valve

Claims (16)

[Claims] 1. A hydraulic multi-circuit brake system, in which the wheel brakes of the driving wheels are integrated into a static brake circuit connected to the outlet pressure chamber of the brake system, In the pressure brake circuit, the ABS device operates on the principle of recirculation, and the ASR device operates on the principle of further decelerating the driving wheels that have a tendency to spin by operating the wheel brakes, and individually controls the brake pressure on the wheel brakes of the driving wheels. This brake pressure control valve is used to control the process of building, holding and dissipating brake pressure during anti-lock control and drive slip control operation, during which the wheel brakes are individually controlled. or connected together with the main brake circuit of the brake circuit and disconnected from it;
Alternatively, a reflux pump is provided which is connected to the return line and the buffer accumulator connected thereto and is designed as a high-pressure pump, the inlet side of which is connected to the return line and the buffer accumulator on the one hand and to the brake system on the other hand. The reflux pump is connected to the brake fluid storage tank of the brake fluid storage tank, and the outlet side is connected to the main brake pipe of the brake circuit of the driving traveling wheels, and the reflux pump is connected to the brake fluid storage tank during the pressure reduction process of the anti-lock control. The amount of brake fluid corresponding to the amount of brake fluid discharged from the receiving wheel brake into the return pipe and buffer accumulator is returned to the outlet pressure chamber of the brake device, and is used as an auxiliary pressure source for drive slip control. The auxiliary pressure source
An ASR device control valve is provided, which conveys the brake fluid from the brake fluid storage tank and/or return pipe and buffer accumulator of the brake equipment to the main brake pipe of the brake circuit of the driven traveling wheels and is designed as a solenoid valve. A
The SR device control valve is in the basic position corresponding to normal operation and braking operation under anti-lock control, that is, the outlet pressure chamber of the brake device attached to the brake circuit of the driving traveling wheel is connected to the main brake pipe of the brake equipment. A can be controlled from the position in which it is applied to the operating position for drive slip control operation, that is, the position in which the main brake piping and the outlet of the reflux pump are blocked from the outlet pressure chamber of the brake device;
A pressure limiting valve is connected in parallel to the SR device control valve, and A
Via this pressure limiting valve, the brake fluid can also be returned to the brake system by means of a return pump when the SR system control valve is in the shut-off position, in which case the brake fluid can be recirculated in the sense of the respective control purpose (anti-lock or drive slip control). The control signals necessary to control the pressure control valve, the reflux pump, and the ASR device control valve are generated by the electronic control unit by processing the output signal of the wheel rotation speed sensor attached to the traveling wheel. Drive slip control devices (ASR devices) and brake antilock devices (ABS devices) in road vehicles, in which several sensors generate electrical signals containing information about the dynamic characteristics of the driving wheels in the form of level and frequency. In, the electronic control unit (43)
generates a control signal when the drive slip control process is interrupted by the end of the drive slip control request state and by the operation of the brake equipment (10), and this control signal causes the reflux pumps (27, 27 ') continues to operate, and the ASR device control valve (71) is held at the cutoff position corresponding to the driving slip control operation, in which case the time width of this delay time width Δtr is such that the brake of the driving traveling wheel is not activated within that time. Because the amount of brake fluid corresponding to the amount previously absorbed by the buffer accumulator (53) of circuit (II) is returned from the brake circuit to the outlet pressure chamber (21) of the brake device (18) attached to it. A drive slip control device (ASR device) and a brake anti-lock device (ABS device) for a road vehicle, characterized in that the size is determined to be sufficient for the following purposes. 2. The electronic control unit (43) has a time delay stage which, upon loss of a signal representing the presence of a drive slip control request condition, causes the reflux pump (27, 27) to stop over a delay time width Δtr. ') maintenance of operation and A.
The ASR device and ABS device according to claim 1, characterized in that the ASR device and the ABS device are controlled to generate a signal for controlling the SR device control valve (71). 3. The buffer accumulator (53) is provided with a pressure monitor (86) that generates an output signal representative of its relaxed state.
), and depending on the output signal, the delay time width Δ
3. ASR device and ABS according to claim 1 or 2, characterized in that upon termination of tr, the reflux pump (27, 27') is shut off and the ASR device control valve (71) is switched to the basic position (0). Device. 4. The damping accumulator (53) is designed as a piston-spring accumulator, and a limit is provided as a signal generator of the pressure monitor to generate an output signal representative of the position of the accumulator piston corresponding to the minimum volume of the accumulator chamber. ASR device and AB according to claim 3, characterized in that a switch (87) is provided.
S device. 5. During drive slip control operation, a reflux pump (
An electronic control unit (4) is installed between the prefill pump (73) that supplies the inlet of the
5. ASR and ABS device according to claim 1, characterized in that a metering valve (91) controlled by the output signal of step 3) is connected thereto. 6. The metering valve (91) is constructed as a two-port, two-position switching solenoid valve, the basic position (0) of which is a cut-off position and the energized position (I) a through-flow position. The ASR device and ABS device according to claim 5. 7. From the outlet (93) of the prefill pump of the supply pipe (88) leading to the reflux pump (27) to the metering valve (9).
A low-pressure accumulator (92) is connected to the parts up to 1), and its storage capacity is the same or almost the same as the maximum swallowing volume of the brakes (16, 17) of the driving traveling wheels. The ASR device and ABS device according to claim 5 or 6. 8. ASR and ABS device according to claim 7, characterized in that the low-pressure accumulator (92) is designed for a maximum accumulator pressure of 15 bar, preferably about 10 bar. 9. The low pressure accumulator (92) is equipped with a pressure monitor (94) or a limit switch (96) that controls the accumulator filling operation of the prefill pump (73).
ASR according to claim 8, characterized in that the ASR is equipped with
equipment and ABS equipment. Claim 10: Brake circuit (II
5. ASR and ABS device according to claim 1, characterized in that the reflux pump (27') of ) is designed as a self-priming pump. [Claim 11] A brake circuit (II) for driving traveling wheels.
) of the brake device (18) attached to the pressure outlet (72
) and the inlet side of the reflux pump (27'), an inlet control valve formed as a 2-port 2-position switching solenoid valve (100) is connected. and ABS equipment. 12. The functional position of the inlet control valve (100) corresponding to the anti-lock control operation is such that the pressure outlet (72) attached to the brake circuit (II) of the driving traveling wheels is connected to the reflux pump of the brake device (18). (27') is in the basic position (0) where it is blocked (blocked) from the inlet side, and the (energized) through-flow position (I) of the inlet control valve (100) corresponds to drive slip control operation. Claim 11 characterized in that
The ASR device and ABS device described. 13. An accumulator (99) is connected between the inlet control valve (100) and the inlet (77, 58) of the reflux pump (27') of the brake circuit (II) of the driving traveling wheels. 12. Claim 11, characterized in that the volume of the accumulator (99) corresponds at least to the maximum intake of the wheel brakes (16, 17) of the brake circuit (II) of the driven traveling wheels and is approximately equal to this volume. or the ASR device and ABS device according to 12. 14. The overpressure generated in the main brake line (24) of the brake circuit (II) of the drive wheel during drive slip control operation is transferred to the brake device (18) and via it to the storage tank (74). A pressure limiting valve that relaxes towards (
81) is the main brake pipe (24) of the brake circuit (II) of the driving traveling wheels and the brake fluid supply pipe (97') leading from the accumulator (99) to the inlet (77, 58) of the reflux pump (27'). 14. The ASR device and ABS according to claim 13, wherein the ASR device is connected between the ASR device and the ABS device.
Device. [Claim 15] The outlet (66) of the reflux pump (27')
) and the brake fluid storage tank (74) of the brake device (18)
A 2-port 2-position switching solenoid valve ( 98) is connected, and this 2-port 2-position switching solenoid valve (98) has a through-flow position corresponding to normal braking operation, the brake pressure holding process and brake pressure re-formation process of anti-lock control, and the anti-lock control 11. The ASR device and ABS device according to claim 10, wherein the ASR device and the ABS device are switched between a cutoff position corresponding to a brake pressure extinction process and a drive slip control process. [Claim 16] 2-port 2-position switching solenoid valve (98)
11. The ASR device and ABS device according to claim 10, wherein the excitation position is a cutoff position corresponding to a drive slip control operation and a pressure extinction process of anti-lock control.